It is not so sickening once you really think about it, considering the situation he was in.
He has a city with population 180. He has been increasing this population using manes, despite the fact that one "person" starves every turn. That means he has been getting A LOT of manes every turn, for a preety long time. In that situation, he could have ruled in any one of a ton of ways (Hurrying every wonder in the world, as an example), he just CHOSE to rule with a huge population, each person providing +1 prod +1 gold (priests).
That points out that the problem is not so much in having a huge population, but rather in the manes being a wee bit too powerful, considering the big numbers they can come in.
Also, when it comes to war, it isnt such a good strat at all. He can build one unit per turn. That means he can be outproduced by a more normal civ with 3 or 4 good cities. Considering the number of Manes he has, I'm guessing he's playing in a Huge map, that means a Kuriotate could have 5 supercities each building the same amount (One unit per turn). That would very effectivelly kill him.
Unless he can spam mercenaries, too, with his surplus gold. Can Infernal build mercenaries? Cant seem to remember